


Open to Him

by NihilismPastry



Series: Requests from Tumblr [21]
Category: Undertale (Video Game)
Genre: Blackmail, F/M, Female Reader, Masturbation, Voyeurism, Yandere Gaster - Freeform, exhibitionist
Language: English
Status: Completed
Published: 2016-12-03
Updated: 2016-12-03
Packaged: 2018-09-03 15:09:40
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,914
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8718628
Author URL: https://archiveofourown.org/users/NihilismPastry/pseuds/NihilismPastry
Summary: Gaster is amazed by all the wonderful things on the surface, especially the human he stalks.





	

**Author's Note:**

> I coerced someone into letting me make this into a request. ^_^
> 
> Anon: I imagine that Classic Gaster, before the void, would've been somewhat of a bookworm and kind of shy. If he were to ever find a way out of the void I think he would be the same, but clingy and kind of yandere (the blackmailing type, I find it hard to imagine him killing anyone unless he was from the underfell au.). It's just a thought.

Getting ripped out of the void was not a nice experience. In fact, he was almost certain that he wouldn't force it on his worst enemy. However, Sans assured him that magic poisoning and electrocution was the only way it would work. Though he was loathe tho believe his younger brother, he didn't have much of a choice. Gaster was now free on a world that was so very different to his own. Monsters had destroyed the barrier, and now lived alongside humans once again. There had been major jumps in technology among both humans and monsters, and there was even hybrid children running around. 

Gaster was eager to explore this new world. And what better way to explore something than through science? Alphys was kind enough to give him a spot in her lab, and he was free to look up whatever he wished. Just so long it remained in the confines of morals, laws, and the miniscule budget the humans put them on. That was all fine with him, Gaster had done research under harsher conditions. 

Amidst all the excitement of a new world and things to explore, he also found himself exploring a new emotion. Every time the human passed by, he felt his magic stir and his gaze followed her steps. She was nothing special, little more than a secretary for the administrator, but he felt a pull he had never felt before. Not quite sure what do about it, he began to catalogue his interactions with her. Writing down any of their conversations, taking notes of her likes and dislikes. He even stole some of the security footage that featured her, hell bent on understanding this anomaly.

Gaster stared at the three months of collecting that was set up on an old table. A journal was held in his actual hands, while his pseudo ones held a series of neon high lighters. With all the evidence he now had, it looked like he was enamoured with the human, which didn't make sense. Yes, she was nice enough, maybe beautiful, and had a patient soul. But it went against all reason for him to like her in that way. There had to be a catalyst, something that made his soul prefer her to anyone else in the world.

He sighed and shut his book, and put it on the table before covering it all away with a sheet. Perhaps he needed to collect more data, because he was clearly missing something. He left his office, double checking the lock, and went out into the lobby. However, he backed up, nearly falling over himself to get back into the hallway. The subject of his dilemma was sitting at the front desk, chatting up a red headed male human. She was smiling, leaning forward slightly, and held eye contact with him.

All signs of interest.

Good grief, could she have picked a less desirable person to try and be her mate. The man was head over the physics department, and worked with Sans. He was a talkative fellow who had a hard time understanding the meaning of 'enough is enough'. He also had quite the credit card debt, and only one PH.D, clearly the sign of an utter moron. Even Sans, with his lack of effort, had managed to scrape in two. 

The human was far too smart to try and smooch this poor excuse for a scientist. She needed something better, someone to challenge her wit...

Gaster scrambled into his lab coat for his phone, and opened up a journaling app. There it was, the reason he liked her so much. She wasn't smart the way he was, but she was clever. In fact, they met when he had made a knot of his phone cord, and she had showed him a trick to get it undone. She had other interesting tricks like that up her sleeves, and deployed them everyday. She often referred to them as practical smarts, and he could appreciate such a useful skill. 

"Gaster?" He looked up from his phone, his magic buzzing from the surprise. The woman had left her desk and was poised in front of the hall, the filth long gone. Gaster flushed, and nearly cracked his screen from how hard he exited out of his app. "You're not gonna take off for lunch? Well, I know you don't eat, but..." She waved a hand. "You know what I mean."

He slipped his phone into his coat and began to sign. ' _I was on my way to storage for some spare parts._ '

The woman nodded. "Heh, figured. You're pretty much married to your job."

Well he was fractured across time and space for the better part of three hundred years. It was long over due for him to work at his craft. He dismissed the teasing from his mind and signed ' _However, if you're on your way to lunch, I would gladly join you.'_

The human's smile faltered. "Uh, I've got some more work to do. Mr. Briggs wants some notes on his desk by tonight, and I'm not even halfway done. Maybe some other time?"

' _Of course, I look forward to it_.' 

Gaster continued down the hall, almost forgetting he was going to the storage room, instead of the elevators.

* * *

Gaster continued to keep a close eye on his human over the next few weeks. Occasionally they would 'bump' into each other, but otherwise she had no contact with him. His current situation with his soul was still the same, it throbed whenever she was near or deigned to acknowledge him. Gaster desperately wanted to do more than greet her every so often and watch from afar. But then, logically, she would say no to any of his advances. While he was financially secure, he realized he was not an easy person to get along with. Then there was the fact he had a bad habit of deforming into shards at any given time. There was also his voice, something between a copier machine and a dying internet connection. Which, funnily enough, he also had almost no control over.

But Gaster was a man of science! He was able to make the most impossible equations possible, and the strangest magic a reality. If he set his mind to it, surely he could find a way for his beloved human to accept him. He stared at his laptop screen, snuggled against his pillows, and using his extra hands to tidy up his room. It was after hours, and most of the staff had left already. However, his human was still at work, typing away at her computer in her cubical. Mr. Briggs had wanted more notes, and expected her to provide them. Meanwhile the old man was going to a party downtown, and use his favorite whore, Duchess. Well, that's what he got from his phone messages, anyway.

Gaster watched the human type away at her work, occasionally yawning or shaking her head. After ten minutes of this she stopped entirely, and slid her phone out of her skirt. She leaned back in her chair and clicked. He couldn't see what she was looking at from the angle of the phone, but it soon became evident from the way she was rubbing her stomach, down to her thighs.

Pornography.

In public no less!

Gaster felt his face warm, but he couldn't let himself look away. Her fingers dipped past her skirt and into her panties, before sliding out again. He could already imagine how soft her skin would be, how warm and pliable. And as she began to pump her fingers into her cunt, he growled and leaned forward. It was probably terrible of him to be watching this, but he didn't care. He'd rather see it than some nosy human. She could loose her job over this, or be seen as indecent. If it wasn't for him...

A dark chuckle reverberated in his chest, and he leaned back in his bed. Yes, he knew now. He knew exactly how he would keep the human for himself. He let a hand trail down to his own arousal and let it loose. There really was no harm in it, not when he knew how to make the human his. 

* * *

You stowed away the last of the notes onto Mr. Briggs's desk, your feet aching and head pounding. It was nearly midnight, and you had worked overtime to help out your boss. The old man was lucky you had no social life, there was no way anyone else could work these crazy hours.  You stifled a yawn and went to the front desk. You couldn't wait for Maggie to come back, it felt like her maternity leave was years instead of weeks. 

A sharp prodding in your shoulder, caused you to turn around, a glare and sharp words already cocked, but they died when you saw it was only Gaster. He was a strange guy that worked in almost every department of the lab, working on personal projects and sticking mostly to monsters. You and Ricky the IT guy were the only exceptions to that rule. He also didn't talk, so you could forgive him for jabbing you like that, even if his finger bones were pretty sharp.

"Hey, haven't seen you in awhile. Uh," You glanced around the hall. "didn't know you were working late too."

' _Indeed I am, but I also want to embark on a new endeavour this evening_.'

"Oh?"

He produced another hand that looked exactly like his skeletal ones, and took his phone out of his pocket. It clicked something, and turned it around to face you. On the small screen was you, sitting at your cubical, and on your computer. Your eyebrows furrowed, and your heart rate began to accelerate. How did he get that footage? You had made sure the security camera couldn't pick you up on their footage. Did he hack into them or something? But Gaster never went to to your actual cubical, just the front desk you'd been manning. 

"Gaster-" Your words stopped, and you felt your face go warm when you saw your fingers slip into your skirt. Oh god, it had to be the night you got bored and frisky. Damn your exhibition streak. You pushed aside the slight arousal at getting caught, and kept your voice firm. "This is illegal. Delete it right now."

' _I will if you agree to a set of terms and conditions_.'

"Why would I agree to that when I can just call the police?"

The skeleton began to sign again. ' _You could, but then your reputation would be dragged through the mud, and the company would fire you soon after_.' That damned smirk became broader. ' _In exchange for deleting this, I wish to escort you on three nights out_.'

"You're blackmailing me for a date?"

A dark purple stained his cheek bones, and his fingers faltered for a moment, before he nodded and opened up his mouth a static garble of words slipping out. "Yes. I-if you'll have me."

Wow.

The way he said it almost made it sound sweet.

"Well, you're not giving me much of a choice are you?"

The normally dull socket shined with a purple light, and he pocketed his phone again. The color in his cheeks became darker, and you had to fight the urge to roll your eyes when he took your hand and brought it to his teeth. "Goodnight, dear."

**Author's Note:**

> So here's the creepy Gaster who's a little bit shy. Towards the end he was such a goober, he's so freaking adorable though. I've never written him this way before, so I hope it wasn't total cringe.
> 
> Know what is total cringe? My tumblr! http://nihilismpastry.tumblr.com


End file.
